I do definately vote for down. I have always lved it on girl and will always do, more that if they're having it up.
When a girl wears her hair down, she symbolize feminine energy, it really shows how amazing beautiful hair girls and women has. There are also many different variation of styles with having it worn out that I like. (Only that can make me melt!)
Eventhough, I do also like hair worn up, but definately not always. But like at proms and other similar things, there is no better thing. When a girl wears her beautiful dress and then her hair nicely tied up. Revealing her neck and chest area, (that can also make me melt!) ;)
There's definitely something to be said for the attractiveness of the curve of a girl's neck, so I think having the hair up is more attractive. That being said, if her neck isn't exactly "shapely", she'd probably be better off keeping hair in front of it at all times.
ok. well this is a question that each guy is different on. most guys like a girl who can quickly put their hair up and play with the boys. it makes us feel like we have the found our girl next door when our girl can be laid back with her hair up. but when we go out to a nice dinner we also really like to see our girl look nice with her hair down or in loose curls. hope this helps. just my opinion.